This invention relates to an improved process and apparatus for melt spinning filaments from synthetic polymers. Melt spun filaments from polymers such as polyester, polyamides and polyolefins, etc. are usually produced by extruding molten polymer through a filter and a spinneret and the filaments so formed are cooled to prevent coalescence and then wound up on a bobbin or forwarded to other processing steps. The way in which the filaments leaving the spinneret are cooled has a pronounced effect on their properties and it is generally accepted that some form of imposed quench is required if uniformity in the cooling of the fibers to be achieved.
Attempts have been made to use concentrated flows of air to cool the filaments. However, it is important that vibrations not be imparted to the filaments during the cooling operation or it could adversely affect the properties of the filaments. There have been many different processes and apparatuses that have been proposed for cooling the filaments. One such device disclosed in U.S. Pat. No. 4,259,048 which teaches quenching the filaments with a single laminar centrifugal discoidal jet of cooling air which impinges perpendicularly against the just extruded yarn close to the die holes of the spinneret.
Another attempt to quench the yarn is disclosed in U.S. Pat. No. 3,969,462 which discloses passing the extruded filaments first through a heated zone which maintains the filament molten for intervals below the spinneret face and subsequently quenching the filaments with a radial outflow of cooling gases. The cooling gases pass through a quench stick which is preferably made of porous material such as ceramic or sintered metal so as to minimize the forces imparted to the filaments during the cooling operation.
Still another attempt to quench the filaments in melt spinning of synthetic fibers is disclosed in U.S. Pat. No. 4,045,534 which teaches passing the filaments directly into a heated sleeve having walls that are imperforate and then leading the filaments to a quenching chamber where they are cooled.